The present invention relates to oscillators and, more particularly, to voltage controlled oscillators wherein a capacitor is charged and discharged between first and second voltage levels.
The prior art is replete with oscillators of the type to which the present invention is related. Typically, prior art oscillators of the type discussed herein require a pair of comparators having an output which switches output level states respectively as a capacitor, which is coupled to an input of the comparators, is charged and then discharged between first and second voltage levels. In addition, some type of latch circuit is generally required that is coupled to the outputs of the two comparators to produce a control signal in response to the output level states of the two comparators. The control signal drives a current circuit which sources current to charge the capacitor when disabled by the control signal and which sinks a current from the capacitor to discharge the same when enabled by the control signal.
Although prior art oscillators of the type discussed above work quite well they are not suited for all kinds of applications. In large and complex custom integrated circuit design it may be necessary to reduce die area required by these prior art types of oscillators in order to be able to reduce manufacturing costs while increasing circuit functions on the integrated chip.
Hence, a need exists for an improved oscillator that requires minimal die area using merged design techniques.